perf/core, x86: Reduce number of CONFIG_X86_LOCAL_APIC macros

The function reserve_pmc_hardware() and release_pmc_hardware()
were hard to read. This patch improves readability of the code by
removing most of the CONFIG_X86_LOCAL_APIC macros.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268826553-19518-2-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>